A generalized type of spiral Bessel beam has been demonstrated by using a spatially displaced helical axicon （HA）. The topological charge of the spiraling Bessel beams is determined by the order of the input Laguerr...A generalized type of spiral Bessel beam has been demonstrated by using a spatially displaced helical axicon （HA）. The topological charge of the spiraling Bessel beams is determined by the order of the input Laguerre Gaussian （LG） beam and the topological charge of the HA. The obtained spiraling Bessel beams have an LG type of modulation along their propagation direction and exhibit annihilation-reconstruction properties. Theoretical analysis is presented, including that of the stability, propagation distance, topological charge, and spiraling dynamic characteristics. The mathematical and numerical results show that the propagation distance and helical revolution of the spiraling Bessel beams can be controlled through choosing appropriate radius of the HA.展开更多
We present the measurements and calculations of the absolute total collision cross sections for a room-temperature gas of helium using^(87)Rb atoms confined in either a magneto-optic or a magnetic quadrupole trap.The ...We present the measurements and calculations of the absolute total collision cross sections for a room-temperature gas of helium using^(87)Rb atoms confined in either a magneto-optic or a magnetic quadrupole trap.The loss rates from the magneto-optic trap and the pure magnetic trap are compared and show significant differences.The collision cross sections as a function of trap depth for helium gas are obtained.These findings are significant for extracting the information about the different cross sections when the trap depth is changed.展开更多
We announce the withdrawal of the article entitled“Measurement of Absolute Atomic Collision Cross Section with Helium Using 87Rb Atoms Confined in Magneto-Optic and Magnetic Traps”,which was published in Chinese Phy...We announce the withdrawal of the article entitled“Measurement of Absolute Atomic Collision Cross Section with Helium Using 87Rb Atoms Confined in Magneto-Optic and Magnetic Traps”,which was published in Chinese Physics Letters[28(4)(2011)043401].The first author,Jicheng Wang,had participated in related research with Professor Kirk Madison’s group at the Department of Physics&Astronomy at the University of British Columbia,Canada from September 2008 to February 2010.Even though consent had been granted for some of the experimental data to be used by Jicheng Wang in his own thesis,its publication had not been authorized.We apologize to Professor K.Madison for the misunderstanding,and to Chinese Physics Letters and the readers of Chinese Physics Letters for any inconvenience this mistake may have caused.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2011CB301801)the National Natural Science Foundation of China(Grant Nos.10974039,11047153,10904027,61008039,and 11104049)+1 种基金the Doctoral Program of Higher Education of China(Grant No.20102302120009)the Fundamental Research Funds for the Central Universities of China(Grant No.2009038)
文摘A generalized type of spiral Bessel beam has been demonstrated by using a spatially displaced helical axicon （HA）. The topological charge of the spiraling Bessel beams is determined by the order of the input Laguerre Gaussian （LG） beam and the topological charge of the HA. The obtained spiraling Bessel beams have an LG type of modulation along their propagation direction and exhibit annihilation-reconstruction properties. Theoretical analysis is presented, including that of the stability, propagation distance, topological charge, and spiraling dynamic characteristics. The mathematical and numerical results show that the propagation distance and helical revolution of the spiraling Bessel beams can be controlled through choosing appropriate radius of the HA.
基金Supported by the National Basic Research Program of China under Grant No 2011CB301801the National Natural Science Foundation of China under Grant No 10974039jointly supported by the State Scholarship of the China Scholarship Council for Study Abroad.
文摘We present the measurements and calculations of the absolute total collision cross sections for a room-temperature gas of helium using^(87)Rb atoms confined in either a magneto-optic or a magnetic quadrupole trap.The loss rates from the magneto-optic trap and the pure magnetic trap are compared and show significant differences.The collision cross sections as a function of trap depth for helium gas are obtained.These findings are significant for extracting the information about the different cross sections when the trap depth is changed.
文摘We announce the withdrawal of the article entitled“Measurement of Absolute Atomic Collision Cross Section with Helium Using 87Rb Atoms Confined in Magneto-Optic and Magnetic Traps”,which was published in Chinese Physics Letters[28(4)(2011)043401].The first author,Jicheng Wang,had participated in related research with Professor Kirk Madison’s group at the Department of Physics&Astronomy at the University of British Columbia,Canada from September 2008 to February 2010.Even though consent had been granted for some of the experimental data to be used by Jicheng Wang in his own thesis,its publication had not been authorized.We apologize to Professor K.Madison for the misunderstanding,and to Chinese Physics Letters and the readers of Chinese Physics Letters for any inconvenience this mistake may have caused.
